Generally, gas burners used for combustion apparatuses such as boilers or water heaters may be divided into Bunsen burners and premixing burners depending on a method of mixing a gas for combustion with air.
In a Bunsen burner, a least amount of first air needed in combustion is supplied to a nozzle part and second excess air is supplied to a portion with flames formed thereon to perform perfect combustion, the Bunsen burner having excellent combustion safety but having a long length of flames because the flames are formed by the second excess air.
On the contrary, a premixing burner employs a method of burning a premixed gas manufactured by previously mixing a gas for combustion with air in a mixing chamber, the premixing burner being operated with a low air ratio to allow highly efficient and highly loaded combustion and of reducing occurrence of pollutants such as carbon monoxides and nitrogen oxides by reducing the entire length of flames simultaneously with decreasing the temperature of flames.
Generally, Bunsen burners are used, but recently premixing burners are mostly used to reduce occurrence of pollutants and minimize a combustion chamber.
Conventional premixing gas burners have a configuration in which air supplied from an air blower and combustion gas supplied via a gas supply pipe are previously mixed with each other inside a burner body and supplied to a burner port provided on top of the burner body.
A conventional burner port has a configuration in which there is a burner port formed on one board-plank formed in the shape of one of a flat panel and a cylinder, the configuration having problems such as a deformation of a burner combustion surface occurring due to thermal stress and imperfect combustion or a backfire caused by a damage of a burner port.
Also, according to a conventional burner port configuration, heat expansion is accumulated by red heat of a burner surface in low loaded combustion in such a way that a great force is applied to a structure for fixing a burner to make the structure vulnerable and to reduce durability thereof.